1. Field of the Invention
This invention relates to a wound golf ball having a center ball consisting of an inner sphere and an enclosure layer.
2. Prior Art
Wound golf balls are generally prepared in the prior art by winding a high elongation thread rubber around a liquid or solid center to form a thread rubber layer, and molding a cover stock of balata rubber or ionomer resin on the thread rubber layer.
As compared with two- and multi-piece solid golf balls, wound golf balls are superior in hitting feel and controllability, but inferior in flight distance upon full driver shots because of an increased spin rate and lofting trajectory. Attempts to reduce the spin rate and increase the flight distance of wound golf balls were made in JP-A 129072/1984 and JP-B 4104/1994 disclosing a center ball with an increased diameter. This proposal, however, suffers from the contradictory problem that making the large diameter center ball harder (higher hardness) exacerbates the feel of the ball and prevents the ball from being deformed sufficiently to travel long, especially upon full shots by low head speed players whereas making the large diameter center ball softer (lower hardness) exacerbates the restitution and flight performance of the ball.
No wound golf balls have been optimized in spin rate and satisfied the requirements of an increased flight distance and good feel upon driver shots at any head speed covering from high to low ranges. There is a desire to have such a golf ball.
The manufacture of wound golf balls includes a thread rubber winding step. Typically the center ball is frozen in order to prevent the center ball from deforming upon winding of thread rubber. An oily substance is usually blended in the center ball for facilitating freezing. The oily substance added, however, can reduce restitution and undesirably increase the temperature dependency of restitution. Additionally, the freezing treatment is a cumbersome step adding to the cost.
Therefore, an object of the invention is to provide a wound golf ball which can eliminate a cumbersome expensive center ball freezing treatment from the winding step to achieve a cost reduction and which is improved in flight performance and hitting feel whether the head speed is high or low.